According to Iran's Tasnim News Agency, Iranian vessels continue to receive warnings from the US Central Command (CENTCOM) ordering them to stop and preventing them from crossing the blockade zone.
The report came a day after Trump announced that the US would lift its blockade on Iran, which would, in turn, remove mines from the Strait of Hormuz and end its closure of the strategic waterway with "no tolls."
However, Tasnim cited Iranian sailors who said that, "After Trump's announcement that the naval blockade had been lifted, some Iranian vessels attempted to cross the blockade line but faced US warnings."
"US forces issued warnings to Iranian ships attempting to cross, ordering them to turn back or face gunfire," they added.
Meanwhile, Mohsen Rezaei, a military adviser to Iran's Supreme Leader Mojtaba Khamenei, said Saturday that Trump "is betraying diplomacy for the third time" by maintaining the naval blockade and presenting what he described as excessive demands during negotiations.
"As expected, the American president is betraying diplomacy for the third time," Rezaei said. "By continuing the naval blockade and overstepping in negotiations, he has proven more than ever that he is not a negotiator and that he is pursuing other objectives."
The latest dispute emerged as the United States warned Saturday that it was "more than capable" of resuming war with Iran if necessary, while Trump insisted that any peace agreement must conform to his red lines, including preventing Tehran from ever developing nuclear weapons.
The White House has signalled that Trump is nearing a decision on a potential agreement, although Tehran has denied that a final deal has been reached to end the conflict.
US sources told AFP that the agreement was awaiting Trump's approval, but no decision was made following a White House Situation Room meeting on Friday.
Speaking at a defence summit in Singapore, US Defence Secretary Pete Hegseth said Washington was "more than capable" of restarting the war. CENTCOM also stated on X that American forces "remain present and vigilant across the region."
Diplomatic efforts were further complicated this week by US strikes on Iran's port of Bandar Abbas and retaliatory Iranian attacks.
Iran's state news agency, IRNA, reported that air defences shot down a drone "belonging to the US-Zionist aggressor enemy" on Saturday, citing a military statement.
Despite the tensions, diplomatic contacts have continued, including discussions aimed at halting Israel's offensive in Lebanon, which Iran insists must be included in any agreement ending the war. Israeli forces reportedly advanced further in Lebanon even as military delegations from both countries met at the Pentagon.
Trump said his priorities in any deal include Iran's commitment never to develop nuclear weapons and the reopening of the blockaded Strait of Hormuz.
"President Trump will only make a deal that is good for America and satisfies his red lines," a White House official told AFP, adding: "Iran can never possess a nuclear weapon."
Iranian Foreign Ministry spokesman Esmaeil Baqaei rejected Trump's conditions, saying the Islamic Republic "said goodbye to the language of 'must' 47 years ago."
He added that exchanges of messages were continuing, but "no final agreement has been reached."
In a social media post, Trump said Tehran would remove mines from the Strait of Hormuz and reopen the waterway with "no tolls," while the United States would lift its blockade.
He also said both countries would coordinate the removal and destruction of Iran's enriched uranium, adding that "no money will be exchanged, until further notice."
However, Iran's Fars News Agency cited sources saying Tehran was demanding "the immediate release of $12 billion" before proceeding to the next phase of negotiations.
The same sources said that regarding the toll-free reopening of Hormuz, "no such clause appears in the text of the agreement," while Trump's claim about destroying Iran's nuclear material was "fundamentally baseless."
Iran's ISNA news agency quoted lawmaker Alireza Salimi as saying that a plan "to implement Iran's management and sovereignty over the Strait of Hormuz will soon be approved by parliament."
Tasnim also reiterated that the US blockade remains in place and that Iranian vessels "are receiving warnings from CENTCOM to stop and not cross the blockade line."
Reflecting uncertainty over the conflicting claims, Ali, a resident of Tonekabon in northern Iran, told AFP: "Both sides are speaking in a way that keeps their supporters satisfied. It's not clear who is telling the truth."
Short link: